1. Field of the Invention
The present invention relates to a lamp cooling apparatus cooling a lamp used as a light source, and to a projection display device provided with the lamp cooling apparatus.
2. Description of Related Art
Various types of image display devices called rear projection display devices have been produced. In these rear projection display devices, a transmission type screen is arranged on the front side of the device, and an image is projected from the back side on the screen. As an image to be projected, an image light corresponding to an image displayed on the display panel is generated by using a lamp such as a xenon lamp as a light source, and guiding the light from the light source to enter a liquid crystal display panel such that the light transmit or reflect the liquid crystal display panel. The generated image light is then guided to enter the back side of the screen to display the image on the screen. In the liquid crystal display panel, the image light may be generated by either one of the following manners. That is, individual panel is used per each primary color signal, and image lights generated at each color panels are combined, or single panel is used to generate the image lights of the respective colors. Instead of the liquid crystal panel, micro mirrors may be driven independently to transform the light from the light source to an image light.
The abovementioned rear projection display devices enable relatively compact configurations of image light generating mechanism such as the light source or the liquid crystal display panel, and further enable the image to be displayed on a large screen. It is therefore relatively easy to obtain a device for displaying an image on a large screen. A screen size may be 50-inch or larger, for example.
Japanese Patent Application Publication No. JP 11-84533 describes an example of this type of the rear projection display devices. Further, Japanese Patent Application Publication No. JP 2003-157715 describes an example of the configuration of a lamp and its vicinity used in the rear projection display devices.